Define: Res Judicata

Res judicata is a Latin term meaning “a matter judged.” It refers to the legal doctrine that prohibits the same parties from relitigating the same claim or issue that has already been adjudicated in a final judgment by a court of competent jurisdiction.

The key elements of res judicata include:

• A final judgment on the merits.
• Identity of parties or their privies.
• Identity of claims or issues raised in the prior litigation.

The purpose of res judicata is to promote finality, certainty, and judicial economy by preventing parties from endlessly relitigating the same disputes and claims.

Res judicata bars claims that were or could have been raised in the prior litigation, including claims arising from the same transaction or occurrence.

Res judicata generally applies to judgments from different jurisdictions if they meet the requirements of finality, identity of parties, and identity of claims or issues.

Res judicata can be waived if parties expressly agree to waive the defence or if they fail to raise it in a timely manner during the subsequent litigation.

Yes, some common exceptions to res judicata include:

• Lack of jurisdiction in the prior court.
• Fraud or collusion in obtaining the prior judgment.
• Violation of due process rights.
• Changes in the law affecting the claim.

Res judicata bars relitigation of entire claims, while collateral estoppel (issue preclusion) bars relitigation of specific issues that were actually litigated and determined in the prior proceeding.

Res judicata can be raised as an affirmative defence in legal pleadings, motions to dismiss, or summary judgement motions during subsequent litigation.